Wireless communication systems transfer data packets between User Equipment (UE) to provide data communication services, like internet access, media streaming, voice calls, and user messaging. Wireless communication systems allow users to move about and communicate over the air with access communication. Some wireless communication systems use Orthogonal Frequency Division Multiplexing (OFDM) to exchange wireless data with UEs. In OFDM communication systems, resource blocks are used to transfer data simultaneously over various time slots and frequency carriers. One popular wireless communication system that uses the resource block allocation scheme of OFDM communication systems is Long Term Evolution (LTE) communication networks.
To expand or enhance the wireless signal coverage of a wireless communication network, wireless communication relays are added to locations not adequately covered by current network infrastructure. A relay exchanges wireless signaling and data between UEs and another wireless access point. Without the signal repetition provided by the wireless relay, the coverage area of the wireless network access point may otherwise have not extended far enough to serve the UEs using the relay. Thus, a wireless relay provides a less resource intensive means for increasing wireless network coverage. Wireless relays typically backhaul traffic through a communication link to a donor base station.
A wireless communication system may employ Carrier Aggregation (CA). CA allows communication networks, such as Long Term Evolution (LTE) networks, to use multiple resource blocks simultaneously for a UE. A UE uses uplink CA to increase data throughput and transmission speeds to a wireless relay or donor base station. Wireless communication systems can aggregate carriers over frequencies bands using Intra-Band Contiguous CA, Intra-Band Non-Contiguous CA, and Inter-Band CA. Intra-Band Contiguous CA uses component carriers that are in the same frequency band and are adjacent to each other. Intra-Band Non-Contiguous CA uses component carriers that are in the same frequency band but are not adjacent to each other. Inter-Band CA uses component carriers that are in different frequency bands.
Power Headroom (PHR) is a type of Media Access Control (MAC) Control Element that reports the headroom between the maximum transmission power available for a UE and the current transmission power is use by the UE. A wireless access point may use PHR measurement reports to determine how much uplink bandwidth a UE can use in a specific subframe before maxing out the transmission power limit. As the UE uses more resource blocks, such as while using uplink CA, more transmission power is used and therefore, a lower amount of PHR is available. Unfortunately, current methods for dynamically controlling uplink CA used by a UE over a wireless relay are neither efficient nor effective.